JP3518714B2 - Transparent paper for inkjet recording - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent paper manufactured by using a pulp which has been subjected to a high degree of beating treatment and to which an inkjet suitability is imparted. . In other words, natural transparent paper that is not an impregnated type is provided with excellent color inkjet aptitude without ink bleeding or overflow. [0002] Conventionally, transparent recording paper has been used as a recording medium for drafting. This transparent recording paper is required to have transparency in order to trace a previously drawn image line and to make a copy without distortion by a positive exposure method (so-called blue printing). Further, a pencil is frequently used as a tool for drawing an object, and writing performance of the pencil has been required. For these reasons, the transparent recording paper has been called tracing paper and has transparency and writability. As a method for producing transparent paper, the pulp as a raw material is highly beaten to sufficiently promote fibrillation, and by having sufficient intra- and inter-fiber bonds, the bond within the pulp and between the pulp is raised, There are two methods: a method of eliminating the air interface (natural type) and a method of impregnating the paper with a resin to eliminate air in the paper (impregnation type). Examples of the natural type include, for example, Japanese Patent Publication No. 45-38729, Japanese Patent Publication No. 46-15723, and Japanese Patent Publication No. 52-31445, and examples of the impregnation type include Japanese Patent Publication No. 54-6645 and Japanese Patent Publication No. 56-6850. JP-A-52-46113, JP-A-52-66710,
JP-A-52-128414, JP-B-59-7840 and the like are listed. As a drawing method on tracing paper, there are a direct drawing by a human hand using a pencil, a crow's mouth, a lot ring and the like, and a plotter as an output of CAD. Previously, the above tools were used as writing instruments for plotters. However, due to recent advances in inkjet recording technology, the above-mentioned writing implements have been replaced by inkjet heads. Therefore, characteristics as an ink jet recording paper have been required for tracing paper. For example, Japanese Patent Application Laid-Open No. Hei 5-177921 discloses a monochromatic ink jet recording paper. In this publication, a styrene-acryl copolymer, a nonanol-based or nonylphenol-based material is formed on the surface of a support. Recording papers coated with a surface size liquid containing at least one type of system penetrant and a water-soluble polymer have been proposed. The support in this publication uses calcium carbonate as a filler, a base paper having a Stechigt sizing degree of 10 to 20 seconds containing an alkyl ketene dimer or an alkenyl succinic anhydride as an internal sizing agent, and has a high ink absorption rate. An ink jet recording paper exhibiting excellent dot shape and print density can be obtained. When the styrene-acrylic copolymer described in this publication was applied to tracing paper, bleeding of the ink was suppressed, and a satisfactory product for monochrome printing was obtained. However, in recent years, as color printing from monochrome has become popular, color printing using tracing paper has also been required. [0006] In color printing, the amount of ink received by the coating layer is large, especially in a superimposed color portion where inks are superposed. Therefore, in order to reliably reproduce an image, a sufficient amount and speed of ink absorption are required, and to achieve this, it is necessary to provide a coating layer using a pigment on the surface of the tracing paper. Further, it is necessary to have a coating layer structure that does not impair the transparency of the tracing paper. According to Japanese Patent Publication No. 53958/1986, a coating layer composed of synthetic silica, an inorganic pigment having a refractive index of 1.44 to 1.55, and a water-soluble polymer adhesive is coated with a tracing paper or a thermoplastic resin. A recording sheet for a second original drawing provided on the surface of a support such as a film has been proposed. It is described that this makes it possible to obtain a tracing paper having high ink absorption, high image density, good resolution, excellent writing properties, and excellent transparency. However, when polyvinyl alcohol as described in the publication is used as the water-soluble polymer adhesive, the polyvinyl alcohol crystallizes with the lapse of time and under moist heat to reduce the ink absorbency, and as a result, the ink bleeds It turned out to be a problem. Even when other water-soluble polymer adhesives described in this publication are used, it is difficult to satisfy the recent demand for higher transparency for transparent paper. Furthermore, better surface properties (no bumps)
Therefore, it has been necessary to study a formulation that satisfies transparency, ink jet suitability and the like with a low coating amount using a water-soluble adhesive other than the water-soluble polymer adhesive described in the publication. [0008] According to Japanese Patent Publication No. 6-427, a support film is formed on at least one side with a film mainly composed of polyvinyl alcohol and polyvinylpyrrolidone. Recording films that have been crosslinked by a reaction have been proposed. In the description, silica, alumina, talc, etc. having an average particle size of 0.01 to 5 μm as an anti-blocking agent
It is described that 1 to 10 parts by weight of the pigment is used based on 100 parts by weight of the total amount of polyvinyl alcohol and polyvinyl pyrrolidone. Further, the thickness of the film is 2 to 2
It is described as 0 μm. In this case, the ink is absorbed in the polyvinyl alcohol + polyvinyl pyrrolidone layer. However, when such a film (coating layer) originally provided on a film is intended to be provided on a natural-type tracing paper, since the amount of coating is large, water in the coating liquid enters the paper, and a drying process is performed. There was a problem that wrinkles and bumps occurred. In order to suppress the generation of wrinkles and bumps in the drying step, drying at a low speed is required, so that the operability is reduced. In addition, wrinkles and lumps are serious drawbacks in quality. SUMMARY OF THE INVENTION [0010] The present invention has been made to solve the above-mentioned problems, and it has been proposed that a transparent paper produced using highly beaten pulp can be used in an inkjet-compatible paper. This is related to a transparent paper for ink jet recording provided with, and it is a transparent type of transparent paper for ink jet recording, which is transparent but does not bleed, overflow, and in particular, does not bleed with time. It is intended to be provided under. Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, have reached the following invention. That is, the transparent paper for ink-jet recording of the present invention is obtained by applying an aqueous coating liquid containing silica and polyvinylpyrrolidone as a main component onto a transparent paper produced using pulp which has been subjected to a high degree of beating treatment. A transparent paper for ink jet recording, wherein the absolute dry coating amount (A + B) of the silica (A) and the polyvinylpyrrolidone (B) is 0.
5 to 2.0 g / m ² , and the mixing ratio (A / B) of silica and polyvinylpyrrolidone on an absolute dry weight basis is 0.
2 to 0.6. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the transparent paper for ink jet recording of the present invention will be described in detail. In the following, the “coating amount” is based on the absolute dry weight. The pulp used in the present invention is one that has been beaten by advanced viscous beating until sufficient internal fibrillation and external fibrillation occur. Because the degree of progress of the beating cannot be measured by the normal drainage evaluation method,
The pulp of the present invention conforms to the Canadian standard freeness specified in JISP8121, and has an absolute dry weight of pulp of 0.5 g per gram.
Diluted to 000 ml and 100 m in Canadian modified freeness using 80-mesh plain woven bronze wire
One that had been beaten to 1 or less was used. Using highly beaten pulp in this way, through sufficient dewatering on the wire with a paper machine and sufficient water squeezing with a press, while controlling shrinkage due to drying with a dryer, avoid rapid drying Carefully dried to obtain a natural type of transparent paper. The pulp used in the present invention is LBK.
P, NBKP, LBSP, NBSP, and various bleached non-wood pulp. In use, they are mixed and used at a ratio according to several purposes. The pulp used in the present invention is 100 ml at the above-mentioned Canadian modified freeness using a beating machine such as a double disc refiner, deluxe finer or Jordan.
Use beaten till below. When making paper using the beaten pulp in the present invention, a paper machine such as a fourdrinier, a circular knit, a twin wire, an on-top or a hybrid can be used. The coating liquid used in the present invention uses silica having a particle size of 1.0 to 5.0 μm as a pigment. Silica is
It is used to cause selective penetration of the ink in the depth direction when the ink adheres to the coating layer. In terms of the writability (pencil abrasion) of the tracing paper, if the particle size of the silica is larger than 5.0 μm, the pencil abrasion becomes high, and if it is smaller than 1.0 μm, the transparency is greatly reduced. . As the binder of the present invention, polyvinylpyrrolidone, which itself has the ability to absorb ink, is used in order to prevent the ink absorbability from decreasing over time and under moist heat. Other binders can also be used in combination.
Examples of other binders include starch, modified starch, and water-soluble polymer compounds such as polyvinyl alcohol.
In this case, it is particularly important to use the ink within a range that does not affect the ink absorbency under humid heat over time. In the present invention, the mixing ratio (A / B) of silica (A) and polyvinylpyrrolidone (B) is important.
A proper range of / B is 0.2 to 0.6. When the coating amount is sufficient (approximately 8.0 g / m ² or more), the higher the proportion of silica, the better. However, the amount of coating that can be applied to natural type transparent paper is at most 2 g.
/ m ² . This is because the transparency decreases as the amount of application increases, and in the case of a natural type tracing paper, the problem of wrinkling at the time of drying tends to occur when the amount of applied water is large, and it is extremely difficult to correct the curl Because it becomes. When the amount of coating is 2 g / m ² or less, the proportion of silica is preferably small, and the A / B is suitably 0.2 to 0.6. If A / B is smaller than 0.2, the ink overflows, and shading unevenness occurs in a solid mark portion or the like.
Regarding this, although polyvinylpyrrolidone itself has an ink absorbing ability, if the silica which is excellent in terms of the ink absorbing ability is reduced, the water repellency of the surface becomes superior due to the interaction, and as a result overflows. Seem.
On the other hand, if A / B is larger than 0.6, the ink bleeds. In the present invention, the aim is to provide ink jet suitability as long as the tracing paper does not lose its transparency. Suitably 0.5 to 2.0 g / m ² per side. 2.0 g / m ²
If the amount is larger than the above range, the transparency will start to decrease, which is not suitable. In addition, a problem of wrinkles and unevenness due to shrinkage at the time of application drying occurs due to an increase in the application amount. Also, 0.5g
If it is less than / m ² , ink bleeding occurs. Although the basic structure of the present invention is very similar to that of the above Japanese Patent Publication No. 6-427, it is disclosed in this publication that the ink is absorbed in a crosslinked polyvinyl alcohol + polyvinylpyrrolidone layer using a support as a film. This is a basic configuration. Further, the ratio of the polyvinyl alcohol / polyvinyl pyrrolidone is preferably 6/4 to 4/6, and it is described that silica is used as a blocking inhibitor in an amount of 1 to 10% based on the total amount of the polyvinyl alcohol and polyvinyl pyrrolidone. This publication requires a large coating amount of 3 to 10 g / m ^{2 in} order to use a film having no ink absorption as a support. When these coating amounts are provided on a natural type tracing paper, wrinkles and lumps are generated during drying, which causes serious operational and quality problems. On the other hand, in the present invention, the coating layer is basically a coating layer for fixing and fixing the dyes and pigments of the ink, and has a structure in which the solvent of the ink is absorbed on the support side. Unlike films, natural-type tracing paper has its own ink absorbing ability.
In addition, because of high density and high smoothness, it is possible to provide a uniform coating layer even with a small coating amount. In this way, by providing the minimum required coating layer, it is possible to eliminate the occurrence of wrinkles and unevenness during drying, and it is possible to obtain ink jet with sufficient suitability. In this publication, the weight ratio of crosslinked polyvinyl alcohol / polyvinylpyrrolidone is from 6/4 to 4 /
6 is stated to be preferred. However, when the coating amount and the weight ratio specified in the present invention are used, the ink absorbency is reduced due to crystallization of polyvinyl alcohol under humid heat over time, and as a result, ink bleeding occurs under such conditions. Resulting in. On the other hand, in the present invention, since the coating layer is formed of a material containing silica and polyvinylpyrrolidone as main components, there is no decrease in the ink absorbency under humid heat over time, so that the above-described problem does not occur. In this publication, use of silica as an antiblocking agent is described. However, since the ratio of silica / (polyvinyl alcohol + polyvinylpyrrolidone) is 0.01-0.1. A problem that ink overflows occurs. On the other hand, in the present invention, the role of silica as a pigment is also different, and as a result, it also acts as an anti-blocking agent. However, basically, as described above, the role of promoting penetration of ink in the depth direction is as described above. It is. Then, by setting the mixing ratio of silica / polyvinylpyrrolidone to 0.2 to 0.6, the overflow of the ink is suppressed. In general, water or an organic solvent can be used as a solvent of a coating solution for a natural-type tracing paper. Among organic solvents, an organic solvent such as an alcohol-based water-miscible solvent is used. Are not suitable as mixed solvents. This is because water is a swelling agent for cellulose, which is a raw material of tracing paper. When water and an organic solvent such as alcohol and acetone are mixed, the surface tension of the solvent itself decreases and enters the amorphous part of cellulose, destroying the fiber-to-fiber bonds between pulp,
Transparency is reduced, and a very large amount of solvent enters the paper, so that it tends to become uneven when dried. Therefore, a water-alcohol-based coating liquid as described in JP-A-5-246130 cannot be used. The coating method used in the present invention includes an air knife, a curtain, a blade, a rod, a gate roll, a gravure, and the like. In the drying method used in the present invention, it is difficult to generate wrinkles and adjust curl only by drying using an air dryer. Therefore, it is preferable to use a drying facility provided with a drum dryer if possible. As a final curl adjustment method, it is desirable to provide a device for spraying steam and a calendar. In some cases, a method of applying water or an aqueous coating solution to the back surface is also selected. In the basic constitution of the present invention, silica and polyvinylpyrrolidone are used, but in addition, a cationic ink fixing agent comprising a secondary amine, a tertiary amine, a quaternary ammonium salt or the like, an antifoaming agent or the like is appropriately used. . The base material of the transparent paper used in the present invention may be a bonding type tracing paper. The bonding type tracing paper is obtained by bonding a natural type tracing paper and a transparent resin film such as polyethylene terephthalate, and an aqueous coating solution can be applied to the tracing paper side. Examples of the bonding method include dry lamination, ultraviolet curing, and electron beam curing. The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.
In the following, "parts" and "application amount" are based on the absolute dry weight. Various properties obtained in the examples and comparative examples were evaluated by the following evaluation methods. <Suitability for ink jet> Plotter design jet 750 manufactured by HP (Hewlett Packard)
Using C, a built-in demonstration sample was printed, and the ink bleeding of the heavy color thin line and the ink overflow of the logo (solid color solid portion) were visually evaluated. Those which were completely absent were evaluated as ○, some were somewhat evaluated as Δ, and some were evaluated as ×. The passing level is △ or higher. <Stability over time> Changes in print quality over time and under heat and humidity were evaluated as stability over time.
The sample conditioned for 1 week at H was printed by the method described above, and the bleeding of the ink was evaluated. Those that were completely absent were evaluated as 、, those that were slightly present were evaluated as △, and those that spread were evaluated as x. The passing level is △ or higher. <Transparency> Transparency is measured according to JIS P8138.
This is a value obtained by subtracting 100% from the opacity measured according to Method B. <Wrinkles and Bumps> The degree of wrinkles and bumps on the paper surface after coating and drying was visually evaluated. Those without wrinkles and lumps were evaluated as ○, those with some were evaluated as Δ, and those with considerable evaluation were evaluated as ×. The passing level is △ or higher. Example 1 Silica (Fine Seal X37B manufactured by Tokuyama Soda: particle size 3.
7 μm) to 100 parts of polyvinylpyrrolidone (BA
500 parts of SF-based Rubiscol K-90: molecular weight 320,000, 30 parts of a water-proofing agent (SR1001: diallylamine-acrylamide copolymer manufactured by Sumitomo Chemical), and 10 parts of a water-repellent (OM6000: ethylene vinyl acetate emulsion manufactured by Kuraray) Part, defoaming agent (Olefin E10 manufactured by Nissin Chemical)
No. 04), and natural-type tracing paper (DX tracing paper N75, manufactured by Mitsubishi Paper Mills, transparency: 72.3%) such that the absolute dry coating amount of silica and polyvinylpyrrolidone is 1.5 g / m ^2. The top was coated with an air knife coater. Table 1 shows properties of the obtained transparent paper for ink jet recording. Example 2 Example 2 was the same as Example 1 except that the number of polyvinylpyrrolidone was 300 parts. Table 1 shows properties of the obtained transparent paper for ink jet recording. Example 3 Example 3 was the same as Example 1 except that the amount of polyvinylpyrrolidone was 170 parts. Table 1 shows properties of the obtained transparent paper for ink jet recording. Examples 4 to 5 The same procedures as in Example 1 were carried out except that the absolutely dry coating amounts of silica and polyvinylpyrrolidone were as shown in Table 1. Table 1 shows properties of the obtained transparent paper for ink jet recording. Examples 6 and 7 The same procedures as in Example 1 were carried out except that the absolutely dry coating amounts of silica and polyvinylpyrrolidone were as shown in Table 1. Table 1 shows properties of the obtained transparent paper for ink jet recording. Comparative Example 1 Example 1 was the same as Example 1 except that the blending number of polyvinylpyrrolidone was changed to 600 parts. Table 1 shows properties of the obtained transparent paper for ink jet recording. Comparative Example 2 Example 1 was the same as Example 1 except that the blending number of polyvinylpyrrolidone was changed to 150 parts. Table 1 shows properties of the obtained transparent paper for ink jet recording. Comparative Examples 3 and 4 The same procedures as in Example 1 were carried out except that the absolutely dry coating amounts of silica and polyvinylpyrrolidone were as shown in Table 1. Table 1 shows properties of the obtained transparent paper for ink jet recording. Comparative Examples 5 to 6 The same procedures as in Example 1 were carried out except that the absolutely dry coating amounts of silica and polyvinylpyrrolidone were as shown in Table 1. Table 1 shows properties of the obtained transparent paper for ink jet recording. Comparative Example 7 Example 2 was the same as Example 2 except that polyvinyl alcohol (Kuraray PVA405) was used instead of polyvinylpyrrolidone. Table 1 shows properties of the obtained transparent paper for ink jet recording. [Table 1] The above Examples and Comparative Examples are summarized in Table 1.
PVP and PVA in the table are the number of parts of polyvinyl pyrrolidone and polyvinyl alcohol, respectively, Si is silica, and Si / P is the mixing ratio of silica / polyvinyl pyrrolidone (polyvinyl alcohol). The application amount is the absolute dry weight per one side. Evaluation: From Examples 1 to 7 in Table 1, the absolute dry coating amount (A) of silica (A) and polyvinyl pyrrolidone (B)
+ B) is in the range of 0.5 to 2.0 g / m ² per side,
And the mixing ratio of silica and polyvinylpyrrolidone (A /
When B) is in the range of 0.2 to 0.6, the transparent paper having excellent ink jet aptitude without bleeding of ink, bleeding under humid heat over time, or overflow of ink wrinkles while maintaining transparency. It can be seen that it can be obtained under the stable operability without the occurrence of bumps. From Comparative Examples 1 and 2 in Table 1, the mixing ratio (A /
If B) is smaller than 0.2, ink overflow occurs, and 0.
When it is larger than 6, it is understood that bleeding occurs. From Comparative Examples 3 to 6 in Table 1, when the absolutely dry coating amount is more than 2.0 g / m ² , wrinkles and bumps are generated, and serious defects in quality as well as operability occur. . It is also found that the transparency is significantly reduced depending on the mixing ratio (A / B). On the other hand, it can be seen that bleeding of the ink occurs where the amount is less than 0.5 g / m ² . Comparative Example 7 shows that when polyvinyl alcohol was used instead of polyvinylpyrrolidone, there was a problem in stability over time, and bleeding occurred due to a decrease in ink absorbency over time. As described above, the transparent paper for ink jet recording of the present invention, that is, the transparent paper produced by using the pulp which has been highly beaten, contains silica and polyvinylpyrrolidone as main components. In a transparent paper for ink jet recording formed by applying an aqueous coating liquid, the silica (A) and the polyvinylpyrrolidone (B) are mixed with a specific absolute dry coating amount and a mixing ratio to maintain the transparency while maintaining transparency. ,
In particular, it has been found that transparent paper for ink jet recording having excellent ink jet suitability without bleeding over time and ink overflowing can be obtained under stable operability without wrinkles and unevenness.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-192589 (JP, A) JP-A-62-160269 (JP, A) JP-A-63-115779 (JP, A) 149040 (JP, A) JP-A-8-20160 (JP, A) JP-A-8-99458 (JP, A) JP-A-8-197836 (JP, A) JP-A-6-184998 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/00

Claims (1)

(57) [Claims 1] An ink jet obtained by applying an aqueous coating liquid containing silica and polyvinylpyrrolidone as a main component on transparent paper produced using highly beaten pulp. A transparent paper for recording, wherein the absolute dry coating amount (A + B) of the silica (A) and the polyvinylpyrrolidone (B) is 0.5 to 2.0 g / m ² per side, and based on the absolute dry weight. The mixing ratio (A / B) of silica and polyvinylpyrrolidone is 0.
A transparent paper for ink-jet recording, which is 2 to 0.6.